System and methods for engine air path condensation management

ABSTRACT

A system and methods for routing condensate collected in a heat exchanger reservoir to either an air intake system or a position in the engine exhaust based on the type of contaminate in the condensate and operating parameters of the engine or the catalyst are described. In one particular example, condensate is routed to a first position along the engine air intake system in a first mode of operation, and a second position upstream of the catalyst along the engine exhaust in a second mode of operation, and a third position downstream of the catalyst along the engine exhaust in a third mode of operation. When substantially no contaminates are detected, the condensate may be routed into the engine exhaust upstream of the catalyst in order to cool the catalyst.

FIELD

The field of the disclosure relates to detection of contaminants incondensate, formed naturally, and collected in a Charge Air Coolercoupled to an engine intake air path and/or exhaust air path wherebyactions are taken in response to the detection.

BACKGROUND AND SUMMARY

Boosted engines are in common use in which air is compressed by an aircompressor powered by either a turbo positioned in the engine exhaust orthe engine crankshaft. Compression will increase air temperature.Consequently the compressed air is often routed through a heat exchangercommonly referred to as a charge air cooler before entering the engineair intake. Under high ambient air humidity conditions condensate willform in the heat exchanger. In some prior approaches condensate isalways routed into the engine exhaust and in other prior approachescondensate is always routed into the engine air intake.

The inventors herein have recognized that always routing the condensateto either the exhaust or the air intake regardless of engine operatingconditions and regardless of whether there are contaminants in thecondensate has led to undesirable engine or catalyst operation. Forexample, always routing condensate to the air intake may result in roughengine operation. And always routing condensate to the exhaust upstreamof a catalyst at low or moderate engine loads may result in undesiredcatalyst cooling. Further, if engine oil is present in the condensaterouting the condensate to the catalyst may result in undesired catalystoperation. Further, throwing away the engine oil by dumping it into theengine exhaust downstream of the catalyst is undesirable from anemissions or efficiency perspective.

The inventors herein have solved these issues by a method, in oneexample, which comprises: routing air through a heat exchanger and intocombustion chambers of the engine; forming condensate in the heatexchanger; and routing the condensate to either the combustion chambersor a position in the engine exhaust based upon both the type ofcontaminate detected within the condensate and operating parameters ofthe engine or the catalyst. For example, in one embodiment a CAC mayincorporate a specific geometry designed into the inlet tanks in orderto separate condensate from the air path, and further direct thecondensate to either the combustion chambers or a position in the engineexhaust based upon the type of contaminate present. In one particularaspect, when the engine is operating at a high load and engine oil isnot present in the contaminate, the condensate is routed into the engineexhaust upstream of the catalyst to cool the catalyst. In anotherexample, when the engine is operating at a high load and engine oil ispresent in the contaminate, the condensate is routed into the enginecombustion chambers to combust the oil without contaminating thecatalyst. In still another aspect, engine power is reduced when enginecoolant is in the condensate to allow the operator to drive to a safeplace without harming the engine.

The above advantages and other advantages, and features of the presentdescription will be readily apparent from the following DetailedDescription when taken alone or in connection with the accompanyingdrawings. It should be understood that the summary above is provided tointroduce in simplified form a selection of concepts that are furtherdescribed in the detailed description. It is not meant to identify keyor essential features of the claimed subject matter, the scope of whichis defined uniquely by the claims that follow the detailed description.Furthermore, the claimed subject matter is not limited toimplementations that solve any disadvantages noted above or in any partof this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages described herein will be more fully understood by readingan example of an embodiment, referred to herein as the DetailedDescription, when taken alone or with reference to the drawings, where:

FIG. 1 is a schematic diagram of an example engine system including acharge air cooler;

FIG. 2 is a schematic diagram of FIG. 1 showing example condensatepathways;

FIG. 3 is an example dual intake system including a heat exchanger andreservoir according to the present disclosure;

FIG. 4 shows an example reservoir and metering valve in greater detail;

FIG. 5 is flow chart of an example method for switching betweenoperational modes to adjust the location where condensate is routed,responsive to the engine operating conditions;

FIG. 6 is a flow chart of the first operational mode illustrating anexample method for routing the condensate to engine air intake;

FIG. 7 is a flow chart of the second and third operational modesillustrating an example method for routing the condensate to the engineexhaust;

FIG. 8 is a graph showing example valve adjustments based on engineoperating conditions;

FIGS. 9-12 show an example condensation management system according to asecond embodiment wherein an accumulator is included for aiding therouting of said condensate;

FIG. 13 illustrates an example method for routing condensate using theaccumulator;

FIG. 14 illustrates an example method for filling the accumulator withpressurized gas; and

FIGS. 15 and 16 show a third embodiment of the condensation managementsystem wherein condensate collects within the intake manifold. FIGS. 3,4, 9-12, and 15-16 are drawn approximately to scale, although otherrelative sizing and positioning may be used.

DETAILED DESCRIPTION

The following description relates to systems and methods for addressingcondensate in a charge air cooler (CAC), including adjusting thelocation where condensate is routed within an engine system, such as thesystem of FIG. 1. Therein, one or more valves may be adjusted to controlthe location where condensate is routed, such as the example pathwaysshown in FIG. 2. In one particular embodiment shown in FIGS. 3 and 4, atwin turbo boosted engine is configured to deliver the condensate tovarious locations based on the type of contaminate present in thecondensate and other operating parameters of the engine or catalyst. Forexample, the engine operating conditions may include catalyst or enginetemperature and condensate formation within the CAC, which may bedetermined using the method illustrated in FIG. 5. Example methods forswitching between engine operating modes to adjust the delivery pathwayare shown at FIGS. 6 and 7. Then, FIG. 8 shows an example graph toillustrate valve adjustments in the example engine system. A secondembodiment of the condensation management system with an accumulator forstoring and using pressurized gas to aid in the routing and movement ofsaid condensate is shown in FIGS. 9-12 while FIGS. 13 and 14 showexample methods for operating the condensation management system withsaid accumulator. In addition, because the lowest point in the enginesystem can reside at locations other than the charge air cooler, FIGS.15 and 16 show a third embodiment wherein condensate is collected in theintake manifold that comprises the lowest point in the air intakesystem.

Referring now to FIG. 1, internal combustion engine 10, comprising aplurality of cylinders, one cylinder of which is shown in FIG. 1, iscontrolled by electronic engine controller 12. Engine 10 includescombustion chamber (cylinder) 30 and cylinder walls 32 with piston 36positioned therein and connected to crankshaft 40. Combustion chamber 30is shown communicating with intake manifold 47 through intake runners(not shown) and exhaust manifold 48 via respective intake valve 52 andexhaust valve 54. Each intake and exhaust valve may be operated by anintake cam 51 and an exhaust cam 53. The opening and closing time ofexhaust valve 54 may be adjusted relative to crankshaft position via camphaser 58. The opening and closing time of intake valve 52 may beadjusted relative to crankshaft position via cam phaser 59. The positionof intake cam 51 may be determined by intake cam sensor 55. The positionof exhaust cam 53 may be determined by exhaust cam sensor 57. In thisway, controller 12 may control the cam timing through phasers 58 and 59.Variable cam timing (VCT) may be either advanced or retarded, dependingon various factors such as engine load and engine speed (RPM).

Fuel injector 66 is shown positioned to inject fuel directly intocombustion chamber 30, which is known to those skilled in the art asdirect injection. Alternatively, fuel may be injected to an intake port,which is known to those skilled in the art as port injection. Fuelinjector 66 delivers liquid fuel in proportion to the pulse width ofsignal FPW from controller 12. Fuel is delivered to fuel injector 66 bya fuel system (not shown) including a fuel tank, fuel pump, and fuelrail (not shown). Fuel injector 66 is supplied operating current fromdriver 68 which responds to controller 12. In one example, a highpressure, dual stage, fuel system is used to generate higher fuelpressures. In addition, intake manifold 47 is shown communicating withoptional electronic throttle 62 which adjusts a position of throttleplate 64 to control air flow from throttle body inlet tube 46.Compressor 162 draws air from air intake 42 to supply the engineaspiration system. Air intake 42 may be part of an induction systemwhich draws in air from one or more ducts (not shown in FIG. 1). The oneor more ducts may draw in cooler or warmer air from outside the vehicleor underneath the hood of the vehicle, respectively. An induction valve(not shown in FIG. 1) may then control the location from which intakeair is drawn into the induction system. The intake air may traveldownstream from the induction valve to the air intake 42, compressoroutlet tube 44, CAC 166, throttle body inlet tube 46, intake manifold47, and the air intake runners to 30 that communicate air to each of thecombustion chambers, comprise an air intake system.

Exhaust gases spin turbine 164 which is coupled to compressor 162 whichin turn compresses the remaining pre-throttle, air path volume. Variousarrangements may be provided to drive the compressor. For asupercharger, compressor 162 may be at least partially driven by theengine and/or an electric machine, and may not include a turbine. Thus,the amount of compression provided to one or more cylinders of theengine via a turbocharger or supercharger may be varied by controller12. Turbocharger waste gate 171 is a valve that allows exhaust gases tobypass turbine 164 via bypass passage 173 when turbocharger waste gate171 is in an open state. Substantially all exhaust gas passes throughturbine 164 when waste gate 171 is in a fully closed position.

Further, in the disclosed embodiments, an exhaust gas recirculation(EGR) system may route a desired portion of exhaust gas from exhaustmanifold 48 to intake manifold 47, or another position along the airintake system, via EGR passage 140. The amount of EGR provided to intakemanifold 47 may be varied by controller 12 via EGR valve 172. Under someconditions, the EGR system may be used to regulate the temperature ofthe air and fuel mixture within the combustion chamber. FIG. 1 shows ahigh pressure EGR system where EGR is routed from upstream of a turbineof a turbocharger to downstream of a compressor of a turbocharger. Inother embodiments, the engine may additionally or alternatively includea low pressure EGR system where EGR is routed from downstream of aturbine of a turbocharger to upstream of a compressor of theturbocharger. When operable, the EGR system may induce the formation ofcondensate from the compressed air, particularly when the compressed airis cooled by the charge air cooler, as described in more detail below.Specifically, EGR contains a large amount of water as it is a combustionby-product. Since EGR is at a relatively high temperature and containssubstantial amounts of water, the dew-point temperature may also berelatively high. Consequently, condensate formation from EGR can be muchhigher than condensate formation from compressing air and lowering it tothe dew-point temperature.

The aspiration system may include one or more charge air coolers (CAC)166 (e.g., an intercooler) to decrease the temperature of theturbocharged or supercharged intake gases. In some embodiments, CAC 166may be an air-to-air heat exchanger, while in other embodiments CAC 166may be an air-to-liquid heat exchanger. CAC 166 may include a valve toselectively modulate the flow velocity of intake air, or liquid coolanttraveling through charge air cooler 166 in response to condensationformation within the charge air cooler. Hot charge air from compressor162 enters the inlet of CAC 166, cools as it travels through the CAC,and then exits to pass though throttle 62 and into engine intakemanifold 47. To aid in cooling the charge air, ambient air flow fromoutside the vehicle may enter engine 10 through a vehicle front end andpass across the CAC. Condensate may further form and accumulate in theCAC in response to a decreasing ambient air temperature, high humidityor rainy weather conditions, when the charge air is cooled below thewater dew point. Condensate may collect at the bottom of CAC 166, whichis then re-introduced to the engine system during an acceleration eventat various locations based on the type of contaminate sensed in thecondensate and operating parameters of the engine or catalyst.

As described in greater detail below, inlet tank assembly 202 is locatedat the bottom of CAC 166 at the lowest point where condensation iscollected. Inlet tank assembly 202 is coupled to first routing valve 210that is controlled by the engine control module (e.g., controller 12)and may be activated based on feedback from a sensor located in the sumpportion of the inlet tank that monitors condensation and/or contaminatelevels therein. With regard to the positioning of the sump portion ofthe inlet tank, in one embodiment, the sump portion of the inlet tankmay be positioned slightly below a plane parallel to the ground that istangential to the lowest point of the CAC inlet tank tubes. Therefore,the condensation may travel through one or more tubes plumbed to theengine system where it enters an orifice designed to atomize thecondensate before injection into the engine system. In particular, themethods described include routing the condensate to either the airintake system or a position in the engine exhaust based upon detecting acontaminate in the condensate in addition to the operating parameters ofthe engine or catalyst. For example, during vehicle operation, therouting may include, directing the condensate to each of the air intakesystem and a position in the exhaust system depending on sensed and/orestimated engine parameters during vehicle operation. Furthermore,routing to the various locations described may occur at distinct times,or in some instances may occur concurrently. In addition, the evacuationtube routings may be run parallel to, adjacent to, and/or otherwisetravel in the near proximity of existing under hood heat sources inorder to heat the liquid media via heat transfer in order to pre-atomizesaid liquid media. Conversely, evacuation tube routings may be run nearcool sources (e.g.,) that may be present along the routing paths inorder to provide additional cooling before entering any of the injectionpoint locations. For example, the condensate may be routed to a firstposition along the engine air intake in a first mode of operation, and asecond position along the engine exhaust in a second mode of operation,and a third position along the engine exhaust in a third mode ofoperation, the first, second, and third modes of operation all beingduring operation of the vehicle, and all occurring at non-overlappingdurations.

By controlling the temperature across the CAC, (e.g., inlet and outletcharge air temperatures) condensate formation may be reduced, whichreduces the chance of engine misfire. In one example, by increasing thecharge air temperature at the CAC inlet, the air traveling through theCAC may be further away from the condensation point, thereby reducingthe amount of condensation. One example of increasing the airtemperature at the CAC inlet may include controlling the temperature ofthe intake air from an induction system. For example, an induction valvemay route warmer air from underneath the hood to the induction systemand through compressor outlet tube 44 to CAC 166.

Distributorless ignition system 88 provides an ignition spark tocombustion chamber 30 via spark plug 92 in response to controller 12.Universal Exhaust Gas Oxygen (UEGO) sensor 126 is shown coupled toexhaust manifold 48 upstream of turbine 164 and light-off catalyst 70,which may be a light-off catalyst having a smaller volume than a largervolume catalytic converter that is mounted under the vehicle body.Light-off catalyst 70 is closely coupled to the exhaust manifold orturbocharger (when applied to a IEM cylinder head) and is designed toheat up more rapidly after an engine start than the underbody catalyst.In this particular example, the underbody catalyst is a three-waycatalyst which oxidizes hydrocarbons and carbon monoxide, and reducesnitrogen oxides. In this example, the underbody catalyst includesmultiple bricks. Other forms of catalytic converters may also be used.The light-off catalyst may be an oxidation catalyst, a three-waycatalyst, or other suitable catalyst. Alternatively, a two-state exhaustgas oxygen sensor may be substituted for UEGO sensor 126.

In some examples, the engine may be coupled to an electric motor/batterysystem in a hybrid vehicle. The hybrid vehicle may have a parallelconfiguration, series configuration, or variation or combinationsthereof. Further, in some examples, other engine configurations may beemployed, for example a diesel engine. The electric motor may be usedduring purging operations to maintain a driver torque demand.

During operation, each cylinder within engine 10 typically undergoes afour stroke cycle: the cycle includes the intake stroke, compressionstroke, expansion stroke, and exhaust stroke. Generally, during theintake stroke, exhaust valve 54 closes and intake valve 52 opens. Air isintroduced into combustion chamber 30 via intake manifold 47, and piston36 moves to the bottom of the cylinder so as to increase the volumewithin combustion chamber 30. The position at which piston 36 is nearthe bottom of the cylinder and at the end of its stroke (e.g. whencombustion chamber 30 is at its largest volume) is typically referred toby those skilled in the art as bottom dead center (BDC). During thecompression stroke, intake valve 52 and exhaust valve 54 are closed.Piston 36 moves toward the cylinder head so as to compress the airwithin combustion chamber 30. The point at which piston 36 is at the endof its stroke and closest to the cylinder head (e.g. when combustionchamber 30 is at its smallest volume) is typically referred to by thoseskilled in the art as top dead center (TDC). In a process hereinafterreferred to as fuel injection, fuel is introduced into the combustionchamber. In a process hereinafter referred to as ignition, the injectedfuel is ignited by known ignition means such as spark plug 92, resultingin combustion. Spark ignition timing may be controlled such that thespark occurs before (advanced) or after (retarded) the manufacturer'sspecified time. For example, spark timing may be retarded from maximumbrake torque (MBT) timing to control engine knock or advanced under highhumidity conditions. In particular, MBT may be advanced to account forthe slow burn rate. During the expansion stroke, the expanding gasespush piston 36 back to BDC. Crankshaft 40 converts piston movement intoa rotational torque of the rotary shaft. Crankshaft 40 may be used todrive alternator 168. Finally, during the exhaust stroke, the exhaustvalve 54 opens to release the combusted air-fuel mixture to exhaustmanifold 48 and the piston returns to TDC. Note that the abovedescription is provided merely as an example, and that intake andexhaust valve opening and/or closing timings may vary, such as toprovide positive or negative valve overlap, late intake valve closing,or various other examples.

In FIG. 1, controller 12 is shown as a microcomputer including:microprocessor unit 102, input/output ports 104, an electronic storagemedium for executable programs and calibration values shown as read-onlymemory 106, random access memory 108, keep alive memory 110, and aconventional data bus. Controller 12 is shown receiving various signalsfrom sensors coupled to engine 10, in addition to those signalspreviously discussed, including: engine coolant temperature (ECT) fromtemperature sensor 112 coupled to cooling sleeve 114; a pedal positionsensor 134 coupled to an accelerator pedal 130 for sensing force appliedby vehicle operator 132; a measurement of engine manifold absolutepressure (MAP) from pressure sensor 122 coupled to intake manifold 47; ameasurement of boost pressure (Boost) from pressure sensor 123; ameasurement of inducted mass air flow (MAF) from mass air flow sensor120; a measurement of throttle position (TP) from a sensor 5; andtemperature at the outlet of a charge air cooler 166 from a temperaturesensor 124. Barometric pressure may also be sensed (sensor not shown)for processing by controller 12. In a preferred aspect of the presentdescription, engine position sensor 118 produces a profile ignitionpickup signal (PIP). This produces a predetermined number of equallyspaced pulses every revolution of the crankshaft from which engine speed(RPM) can be determined. Note that various combinations of the abovesensors may be used, such as a MAF sensor without a MAP sensor, or viceversa. During stoichiometric operation, the MAP sensor can give anindication of engine torque. Further, this sensor, along with thedetected engine speed, can provide an estimate of charge (including air)inducted into the cylinder. Other sensors not depicted may also bepresent, such as a sensor for determining the intake air velocity at theinlet of the charge air cooler, for example.

Furthermore, controller 12 may communicate with various actuators, whichmay include engine actuators such as fuel or condensate injectors, anelectronically controlled intake air throttle plate, spark plugs,camshafts, etc. Various engine actuators may be controlled to provide ormaintain torque demand as specified by the vehicle operator 132. Theseactuators may adjust certain engine control parameters including:variable cam timing (VCT), the air-to-fuel ratio (AFR), alternatorloading, spark timing, throttle position, etc. For example, when anincrease in PP is indicated (e.g., during a tip-in) from pedal positionsensor 134, torque demand is increased.

Now turning to FIG. 2, a simplified schematic diagram of FIG. 1 is shownthat includes example condensate pathways according to the presentdisclosure. For simplicity, condensate management system 200 is showncoupled to a single turbocharger system and single exhaust system.However, in some embodiments, engine 10 may include two or moreturbochargers and/or exhaust systems in communication with condensatemanagement system 200. According to the present disclosure, engine 10includes an air intake system and a catalyst coupled to the engineexhaust. Therein, the method comprises routing air through a heatexchanger and into the air intake system; forming a condensate in theheat exchanger; and routing the condensate to either the air intakesystem or a position in the engine exhaust based upon a contaminate inthe condensate and operating parameters of the engine or catalyst.

For example, as the diagram of FIG. 2 schematically illustrates,condensate may collect at the bottom of CAC 166 in inlet tank assembly202. Then, based on the composition and/or level of the condensate, itmay travel through one or more tubes before injection back into engine10. Thus, the position of first routing valve 210 that is under thecontrol of control system 12 may be adjusted to route condensate to afirst position along the engine air intake system (e.g., intake manifold47) in a first mode of operation, and to the engine exhaust when notoperating in the first mode. In addition, second routing valve 212 isincluded for routing the condensate to a second position along theengine exhaust upstream of light-off catalyst 70 in a second mode ofoperation, and to a third position along the engine exhaust downstreamof light-off catalyst in a third mode of operation.

With regard to the engine modes shown in the exemplary embodiment ofFIG. 2, the first position is in engine intake manifold 47 and the firstmode of operation comprises engine operation at a high load with thecontaminate including engine oil. Therefore, when a sensor (e.g.,condensate sensor 410 described in detail below) detects the presence ofengine oil in the condensate, for example, because the engine oil isdetected by a sensor coupled to a condensate reservoir, first routingvalve 210, which is shown as a two-way valve, may be adjusted to directthe condensate contaminated with engine oil through first pathway 220where the condensate is atomized by first metering valve 930 before itenters the intake air stream for delivery into cylinder 30. Thereby, theengine oil may be more substantially burned during the combustionprocess occurring therein. Alternatively, if engine 10 is not operatingunder a high load, for example, because the load on the engine is belowa threshold, but condensate sensor 410 still detects engine oil as thecontaminate, engine 10 may still operate in the first mode of operationunder fuel enrichment conditions. Operation with excess fuel under fuelenrichment conditions will tolerate induction of the condensate withouteffecting combustion stability.

Alternatively, if substantially no contaminate is detected by condensatesensor 410, the condensate may be directed to the engine exhaust forinjection therein. Therefore, first routing valve 210 may be adjusted todeliver condensate collected at the bottom of CAC 166 through secondpathway 222 to the engine exhaust. In addition, because the condensatecollected comprises substantially pure water when no contaminate ispresent, the methods according to the present disclosure includeinjecting condensate upstream of the catalyst based on one or moreengine or catalyst parameters. For example, when the catalyst becomeshot because a temperature is greater than a threshold, the condensatemay be injected into the exhaust system upstream of light-off catalyst70 for delivery therein. Therefore, the condensate may be routed intothe engine exhaust upstream of the catalyst in order to cool the devicewhile the load on the engine is high. In this way, the methods accordingto the present disclosure advantageously use moisture collected withinthe engine system to increase the efficiency of the charge air coolingsystem. Accordingly, with regard to FIG. 2, second routing valve 212 maytherefore be adjusted to direct the condensate within the exhaustsystem. Because two positions are present within the exhaust system,herein the second position is the location upstream of the catalyst andthe third position is the location downstream of the catalyst.

The second mode of operation comprises injecting condensate at thesecond position that is along the engine exhaust upstream of thecatalyst while engine 10 operates at a high load with said contaminatebeing substantially free of engine oil. Therefore, when the load on theengine is high (e.g., above a load threshold), the catalyst temperaturemay increase in response to the high load such that the catalysttemperature becomes greater than a temperature threshold. When thisoccurs, second routing valve 212 may be actuated to direct condensatethrough third pathway 224 and into second metering valve 232 that islocated in said second position. As described above, the condensate maythereby act to cool the catalyst while the load on the engine is high.In addition, the second mode of operation further comprises the catalystoperating at a temperature inferred to be above a predeterminedtemperature while the contaminate is substantially free of engine oil.The catalyst temperature may be inferred from one or more of thefollowing variables: combustion air/fuel ratio, exhaust gasrecirculation, engine speed, ignition timing, and airflow through theengine. For example, U.S. Pat. No. 5,303,168 teaches a method forpredicting engine exhaust gas temperature during engine operation.Therein, various engine information is processed to dynamically predictthe exhaust temperature based on vehicle operations using predictivemodels while the engine speed, load, spark advance, exhaust gasrecirculation percent and air/fuel ratio vary.

The third mode of operation comprises injecting condensate at the thirdposition that is along the engine exhaust downstream of the catalystwhile engine 10 operates at a low load and no significant engine oil isdetected in the condensate. Therefore, when the load on the engine islow (e.g., below a threshold), the catalyst temperature may also fallbelow a temperature threshold. When this occurs, second routing valve212 may be actuated to direct condensate through fourth pathway 226 andinto third metering valve 234 that is located in the third positiondownstream of light-off catalyst 70. Upon traveling through secondpathway 222, and further through fourth pathway 226, third meteringvalve 234 may atomize the condensate before it enters the exhaust airstream post light-off catalyst. This may be done in order to protect thelight-off catalyst from being exposed to excess moisture during vehicleoperations. Further, while operating at light engine loads, injectingcondensate upstream of the catalyst could cause undesired cooling of thecatalyst and less efficient catalytic operation.

Although the system and methods described herein may freely operate inany of the positions based on one or more engine and/or catalystparameters, the third mode of operation wherein the condensate is routedto the third position may occur more often than the operation in thesecond mode wherein the condensate is routed to the second position orthe operation in the first mode wherein the condensate is routed to thefirst position. As such, the condensate comprising substantially purewater may be safely purged from the engine system while the engineoperates under reasonable engine loads. In addition, the inventors haverecognized that always routing condensate to either the exhaust or airintake regardless of engine operating conditions and regardless ofwhether there are contaminants in the condensate has led to undesirableengine or catalyst operation, which is thereby avoided by using thesystem and methods according to the present disclosure.

In some instances, the contaminant detected within the condensate may beengine coolant. However, detection of engine coolant within thecondensate signifies potential issues within the engine system since acoolant leak is likely present. Therefore, when the contaminate detectedis engine coolant, the described methods further comprise reducing powerto the engine to allow the operator to drive to a safe place withoutharming the engine. In this way, the described system and methods allowfor a limp home mode to allow the vehicle to be operated under arestricted set of conditions until arrival at a destination where thevehicle may be parked until maintenance is performed on the vehicle toremedy the potential issue.

Engine system 10 may further include control system 14 comprisingcontroller 12 that is shown receiving information from a plurality ofsensors (various examples of which are described herein) and sendingcontrol signals to a plurality of actuators (various examples of whichare described herein). As one example, sensors may include condensatesensor 410 coupled to inlet tank assembly 202, sensors in the intake,exhaust gas sensor and temperature sensors located in the exhaust and/orcatalyst, etc. Other sensors such as pressure, temperature, fuel level,air/fuel ratio, and composition sensors may be coupled to variouslocations in engine 10. As another example, the actuators may includecondensate metering valves 930, 232, and 234, fuel injector 66, andthrottle 62. The controller may receive input data from the varioussensors, process the input data, and trigger the actuators in responseto the processed input data based on instructions or code programmedtherein corresponding to one or more routines. Example routines areshown in FIGS. 5-7.

Turning now to FIGS. 1-3, which shows the relative positioning ofcomponents in an example twin turbo engine (e.g., two turbochargers andtwo exhaust manifolds) comprising a condensate management system thatincludes a heat exchanger and reservoir according to the presentdisclosure. As shown, inlet tank assembly 202 is located below CAC 166at the lowest point where condensation will collect. Therefore, as airenters each turbocharger compressor inlet identified at 180, airflowthrough intake passage 42 may be directed to compressor 162 and continuethrough compressor outlet tube 44 in the manner described above withrespect to FIGS. 1 and 2. At CAC 166, both airflows are combined into asingle airflow that is forced through said heat exchanger. Thereafter,the compressed and cooled airflow is directed through the throttle bodyinlet tube 46, through the intake manifold 47 and into the intakerunners, ultimately reaching combustion chambers 30. To aid in coolingthe charge air, an ambient air flow from outside the vehicle may enterengine 10 through a vehicle front end as it is further passed across CAC166.

As indicated in FIG. 3 and described above, inlet tank assembly 202 islocated below CAC 166 for collecting condensate as it forms within theair intake system. However, because the condensate management systemshown in FIG. 3 is coupled to a system with two exhaust manifolds (notshown), in some instances, first routing valve 210 may be a three-wayvalve configured to direct condensate collected to the engine intakesystem via first pathway 220 or to simultaneously direct collectedcondensate to each engine exhaust system via two second pathways 222.Although condensate flow to each engine exhaust through second pathway222 may occur simultaneously, this is non-limiting and in someembodiments, condensate may be directed to one or the other exhaustmanifolds based on the needs therein. For example, if one exhaust pipeis designed to carry a heavier load, for instance, because it has anextra catalyst present, condensate may be routed to that exhaust systemmore frequently compared to the other exhaust system. For simplicity,herein each exhaust system is substantially identical so the loadcarried by each is uniformly distributed between the two exhaustmanifolds. As such, the flow of condensate to each exhaust manifold maygenerally occur in proportion to one another. Furthermore, as describedwith respect to FIG. 2, condensate routed to the exhaust system maytravel through second pathway 222 en route to second routing valve 212.

FIG. 4 shows example inlet tank assembly 202 in greater detail. In oneembodiment, inlet tank assembly 202 includes a single sensor fordetermining whether a contaminate is present in the condensate. However,this is non-limiting, and in other embodiments, two or more sensors mayalso be present to detect one or more contaminates in addition to aclean condensate. For example, three sensors may be included todetermine whether the condensate is substantially free of contaminates,whether engine oil is present as the contaminate, and/or whether thecontaminate is engine coolant. Therefore, as shown in FIG. 4, condensatesensor 410 may discriminate between these three fluids. For instance,the condensate may be analyzed for a specific gravity or hydrocarbonsignature of the condensate media since engine coolant contains ethyleneglycol that exhibits a different hydrocarbon signature than engine oil.

Because inlet tank assembly 202 is located below CAC 166, condensatefrom the charge air cooler may flow downward to the lowest point thatcoincides with internal sump 402 where the condensate is collected. Forthis reason, communication port 404 joins both left and right fluidchannels together, to effectively funnel condensate within CAC 166 intointernal sump 402 for evacuation. Since the condensate is re-introducedwithin the engine system, inlet tank assembly 202 further includesfilter 406 to restrict any particles or debris from entering thecondensation evacuation tube, or condensation management system.Therefore, condensate fluids that proceed further downstream (as shownin FIG. 4) to first routing valve 210 may be cleaner since particulatematter is decreased through use of the filter. In some embodiments,internal sump 402 may include removable plug 412 in order to provide aport for gaining access to the internal sump area. For example, during atesting phase, a camera may be installed in the port to visualize thefluids while one or more sensors determines whether a contaminate ispresent in the collected condensate. As described in greater detailabove with respect to FIG. 3, collected condensate may also be routed tothe three positions based on the type of contaminate in the condensateand operating parameters of the engine or catalyst.

Turning to control of the system and methods disclosed, FIGS. 5-7 showexample flow charts to illustrate how controller 12 may be programmed tomake adjustments within engine 10 to switch between engine operatingmodes. For example, controller 12 may switch operating modes byactuating one or more routing valves in the condensation managementsystem to adjust the pathway traveled by the condensate as it is routedto the various locations described.

FIG. 5 is flow chart of method 500 for managing engine 10 whileswitching engine operating modes based on the condensate identity (e.g.,whether a contaminate is present). According to the example flow chartshown, method 500 therefore generally includes discriminating betweenclean condensate comprising substantially all water and condensatecontaminated with impurities like engine oil or coolant. Then, dependingon the identity of condensate sensed, method 500 further comprisesswitching between engine operating modes to route the condensate to thelocations disclosed in FIG. 2. As described there, method 500 includescompressing air in a compressor driven by a turbo coupled to the engineexhaust upstream of the catalyst; forcing said compressed air through aheat exchanger into the engine air intake; collecting condensate formedby the heat exchanger in a reservoir; and routing said condensate to oneof: the engine air intake system; the engine exhaust upstream of thecatalyst and downstream of the turbo; or the engine exhaust downstreamof the catalyst.

As such, controller 12 may be coupled to inlet tank assembly 202 andspecifically condensate sensor 410 to determine whether any condensatehas collected within the reservoir. At 502, method 500 thereforeincludes monitoring condensate levels within the reservoir, e.g.,internal sump 402. At 504, method 500 further includes determiningwhether the volume of condensate collected is greater than a volumethreshold. If a substantial amount of condensate has been collected, forexample, because the condensate collected is greater than the volumethreshold, the method may further determine the purity of the condensatecollected within the reservoir. Alternatively, if the amount ofcondensate collected falls below the volume threshold, in the embodimentdescribed engine 10 may continue operating while controller 12 monitorscondensate conditions within the reservoir. For simplicity, while thevolume of condensate falls below the volume threshold, herein the flowof condensate is ceased. However, in some embodiments controller 12 mayoptionally route condensate collected within the reservoir based on theengine conditions regardless of the volume collected so long as somecondensate is present in the reservoir.

With respect to the purity of condensate sensed, at 506, method 500includes determining whether a contaminate is present in the condensate.As described briefly above with respect to FIG. 2, at 508, method 500further comprises determining whether the contaminate is engine oil. Ifthe contaminate is engine oil, at 510, engine 10 may operate in thefirst operating mode by routing condensate to the first position locatedin the engine intake manifold. FIG. 6 shows an example flow chartillustrating how controller 12 may operate the condensate managementsystem in the first operating mode based on the engine operatingconditions when the contaminate is engine oil.

In some instances, the contaminate may be engine coolant. Therefore,method 500 further includes determining whether coolant is presentwithin the condensate. For example, condensate sensor 410 may beconfigured to discriminate between engine oil and coolant by accountingfor the specific gravity of each substance, which may be different dueto a different hydrocarbon signature of the media. For instance, enginecoolant may contain ethylene glycol and therefore have a differenthydrocarbon signature than engine oil that may contain hydrocarbonshaving up to 34 carbon atoms per molecule. In addition, although manymotor oils have between 18 and 34 hydrocarbons per molecule, this isnon-limiting and in some cases more than 34 carbon atoms may be presentper molecule. For this reason, if the contaminate sensed is not engineoil, at 520, method 500 includes reducing power to the engine since thecontaminate is likely to be engine coolant. Furthermore, because anengine coolant contaminate is indicative of a leak within the enginesystem, and is therefore indicative of potential issues, the methodfurther comprises confirming that the contaminate is coolant, forexample, by analyzing the hydrocarbon signature collected fromcondensate sensor 410. Upon confirmation, at 522, method 500 includessetting a warning indicator such as a dashboard light to communicatethat a leak is present within the engine system. Moreover, the methodcomprises reducing power to the engine when engine coolant is present inthe condensate to allow the operator to drive to a safe place withoutharming the engine. This limp home mode of operation thereby allows thedegraded engine system to be driven to safety until the vehicle can betaken to a repair facility to address or fix the potential issue.

Returning to 506, if no contaminate is detected in the condensate suchthat the condensate is a substantially clean liquid (e.g., water), thenthe method may proceed to 530 wherein the engine operates in the secondor third modes by routing condensate into the engine exhaust eitherupstream or downstream of the catalyst, respectively. FIG. 7 shows anexample flow chart illustrating how controller 12 may operate thecondensate management system in the second or third operating modesbased on the engine operating conditions in the absence of contaminates.

Now, turning to the various engine operating modes, FIG. 6 is a flowchart of method 600 that illustrates the first mode for routing thecondensate to the engine air intake when the contaminate is engine oil.At 602, the routine begins by estimating and/or measuring engineoperating conditions. Engine operating conditions may include enginespeed and load, engine temperatures, throttle position, air mass flow,engine airflow rate, CAC conditions (inlet and outlet temperature, inletand outlet pressure, etc.), ambient temperature and humidity, MAP, andboost level. Condensate formation, such as an amount or volume ofcondensate in the CAC, may be determined based on this data at 602. Inone example, a rate of condensate formation may be determined within theCAC based on ambient temperature, CAC outlet temperature, CAC outletpressure ratio to ambient pressure, air mass flow, EGR, and humidity.The rate may then be used to calculate the amount or level of condensatein the CAC. In another example, a condensation formation value may bemapped to CAC outlet temperature and a ratio of CAC pressure to ambientpressure. In an alternate example, the condensation formation value maybe mapped to CAC outlet temperature and engine load. Engine load may bea function of air mass, torque, accelerator pedal position, and throttleposition, and thus may provide an indication of the air flow velocitythrough the CAC. For example, a moderate engine load combined with arelatively cool CAC outlet temperature may indicate a high condensationformation value, due to the cool surfaces of the CAC and relatively lowintake air flow velocity. The map may further include a modifier forambient temperature. However, as described herein, the amount ofcondensate present in inlet tank assembly 202 may be measured by asingle sensor.

At 604 the routine determines if the engine output is above a first loadthreshold (e.g., because engine RPM's are greater than a desiredoutput). If the engine load is high, at 606, the routine includesactivating first metering valve 930 and routing the condensate/oilmixture there through along a first position in the engine air intakesystem. As one example, controller 12 may adjust the flow of condensateby adjusting first routing valve 210 to a first position that allows thecondensate to flow from inlet tank assembly 202 through first pathway220 and into first metering valve 930. Although routing valve 210 canassume one of two positions as shown in FIG. 2 (e.g., because it istwo-way valve), other valve configurations comprising more pathways fordiverting the flow of condensate within the condensate management systemare possible. However, for simplicity, catalyst locations describedherein allow for increased savings since less material is used forrouting the condensate throughout the evacuation tubes/lines. Inaddition to controlling the direction or pathway of condensate flow, thecondensate management system may further control the rate of delivery inorder to prevent or manage condensation build-up during conditions inwhich condensation is produced, such as during rain or high humidity.Thus, at 608, method 600 includes metering the rate of condensatedelivery based on one or more engine operating conditions. Furthermore,when the engine is operating at a high load and engine oil is present insaid condensate, the method may include routing said condensate into theengine air intake system at an increased rate of delivery since it islikely to be collected at a higher rate.

Returning to 604, method 600 includes making further adjustments toroute the condensate into the air intake when engine oil is present inthe condensate and the engine is operating under fuel enrichmentconditions, even though the load on the engine is low or moderate.Therefore, even though the output of the engine falls below the firstload threshold, at 610, the routine further comprises routing thecondensate/oil mixture to first metering valve 930 along the engine airintake during fuel enrichment conditions. As described above, this maybe done by adjusting the position of first routing valve 210 to directthe flow of condensate through first pathway 220. Alternatively, if theoutput of the engine is low or moderate and no fuel enrichment is tooccur, at 620, method 600 includes determining whether the engine outputfalls below a second load threshold.

When the engine output falls below the second load threshold, and thecondensate is introduced at a single location or port; (e.g., at apositive crankcase ventilation or PCV valve location) reduced airflowswithin the intake system (e.g., due to lower air path velocities) makeit more difficult to distribute injected condensate evenly to all of thecylinders since the atomized mixture tends to settle along the floor ofthe air duct. Conversely, when the engine output is high, increasedairflows (e.g., with high air path velocities) allow for the condensatemixture to hang in suspension as the atomized mixture passes through theair ducts, which advantageously reduces distribution challenges.Therefore, to overcome the distribution challenges, in one example, amulti-port system comprising a separate evacuation tube placed directlyabove each intake port leading to each individual engine cylinder may beutilized. For example, FIG. 9A shows example multi-port system 900 fordistributing the routed condensate to each individual cylinder. Forsimplicity, the location of each evacuation tube relative to eachcylinder (e.g., placed directly above) is shown for reference. (e.g.,see FIG. 9). Alternatively, in another example, an accumulator may alsobe included within the condensate management system to assist condensateevacuation to any or all of the evacuation locations (e.g., to theintake and/or exhaust system) when the engine output falls below thesecond load threshold. In one instance, the accumulator may harvest andstore engine boost pressure and/or an engine intake manifold vacuumparameter to be used on demand. Alternatively, at 622, method 600includes routing the condensate/oil mixture to the third position alongthe engine exhaust downstream of the exhaust catalyst when the engineoutput falls below the second load threshold. Moreover, controller 12may adjust first routing valve 210 and second routing valve 212 in orderto adjust the pathway for delivery to the engine exhaust downstream ofthe catalyst. Alternatively, if the engine output is greater than thesecond load threshold, controller 12 may route the condensate/oilmixture to the first position along the engine air intake as describedabove. Therefore, method 600 proceeds to 606 and further comprisesmetering the condensate while the metered condensate is routed to theintake manifold when the engine is operating at a light or moderateload. For example, as described above, condensate may be routed to thefirst position at the engine intake system when engine oil is detectedin the condensate. Although two load thresholds are herein described, insome instances, the first and second load threshold may be substantiallyequal such that condensate is simply routed to the engine air intakewhile the engine operates above the first load threshold and to theengine exhaust while the engine operates below the first load threshold.

With respect to routing of the clean condensate, FIG. 7 shows a flowchart of method 700 that illustrates the second and third operatingmodes for routing the condensate to the engine exhaust. As describedabove, at 702, the routine begins by estimating and/or measuring engineoperating conditions. Then, at 704, method 700 includes determiningwhether the engine output is above a third load threshold. The thirdload threshold indicates engine conditions above which the catalyst islikely to become hot. Therefore, if the catalyst temperature increases,for example, because the engine output is high, at 706 the cleancondensate may be routed to the second position along the engine exhaustupstream of the catalyst in order to cool the catalyst by spraying thefinely atomized mist into the engine exhaust. As described brieflyabove, routing the clean condensate to the second position may involvecontroller 12 adjusting first routing valve 210 and second routing valve212 to adjust the pathway for delivery of the fluid to the secondposition. Moreover, depending on the engine conditions detected, at 708,method 700 includes metering the rate of condensate delivery based onone or more engine operating conditions. For example, if the engine loadand therefore catalyst temperature increases, the amount of cleancondensate injected may be increased to further increase the rate ofcatalyst cooling. Alternatively, if the engine load decreases, which maycause a decreased catalyst temperature in some instances, the amount ofclean condensate injected may be decreased in proportion to thedecreased engine load or catalyst temperature. Although not shown, insome embodiments, method 700 may include routing said condensate intothe engine exhaust upstream of the catalyst and downstream of the turbowhen the engine is operating under fuel enrichment conditions and engineoil is not present in said condensate.

Returning to 704, if the engine output falls below the third loadthreshold, the temperature of the catalyst may still rise above atemperature threshold based on the engine operating conditions. Forexample, if a moderate engine load that falls just below the third loadthreshold is applied for an extended period of time, the temperature ofthe catalyst may still increase above a temperature threshold that isset to indicate potentially degrading conditions. Therefore, said secondmode of operation comprises the catalyst operating at a temperatureinferred to be above a predetermined temperature with said contaminatebeing substantially free of engine oil. As described herein, thecatalyst temperature may be measured by a sensor (e.g., a temperaturesensor) or inferred from one or more of the following variables:combustion air/fuel ratio, exhaust gas recirculation, engine speed,ignition timing, and airflow through the engine. As such, at 710, if thecatalyst temperature is above a temperature threshold, the cleancondensate may be routed to the second position along the engine exhaustin the manner described already. Alternatively, if the catalysttemperature falls below the temperature threshold while the load on theengine is moderately low, at 720, the clean condensate may instead berouted to the third position along the engine exhaust as indicated at722 for discharge to the atmosphere by adjusting the first and secondrouting valves within the condensation management system. Instead, ifthe engine output falls below a fourth load threshold, at 724, the cleancondensate may be routed to the first position along the engine airintake system by simply adjusting the first routing valve. Thereafter,the rate of condensate delivery may be adjusted based on the engineoperating conditions.

Now turning to FIG. 8, graph 800 shows example valve adjustments basedon engine operating conditions. Specifically, graph 800 shows changes inrouting valve positions in response to changes in pedal position at plot802, engine output at plot 804, and changes in CAC condensate level atplot 806. Additionally, power to the condensate management system (CMS)is shown at plot 808, while the CMS operating mode is shown at 810. Theposition of the first routing valve is shown at 812 while the positionof the second routing valve is shown at 814. Time is shown along theabscissa of each plot and time increases from left to right. Forsimplicity, graph 800 shows example valve adjustments during a firsttime period when condensate sensor 410 detects no contaminates in thecollected fluid. Then, example adjustments are shown for a second timeperiod occurring at some later time when condensate sensor 410 hasdetected an engine oil contaminate in the fluid collected. Although notshown in graph 800, the condensate management system may also detectcoolant in the condensate and reduce power to the engine responsive tothe coolant detected as was described already.

Prior to time t1, the vehicle speed represented as pedal position (PP,plot 802) and engine load (plot 804) may be low and the throttle openingtherefore small. CAC condensate level (plot 806) may therefore fallbelow a threshold volume. In response to an engine warm-up condition(e.g., engine and catalyst temperature below a temperature threshold),the condensation management system may be inoperable and thereforeoccupy the off position. However, in other examples, the CMS may simplybe on for the entire time duration in which the vehicle is on. Becausethe condensation level falls below a volume threshold, the routingvalves may occupy any position since no condensate is being deliveredtherethrough. For simplicity, both routing valves are shown in theirfirst positions, respectively. That is, first routing valve 210 ispositioned to deliver condensate to the first position, and secondrouting valve 212 is positioned to deliver condensate to the secondposition upstream of the catalyst.

Between time t1 and time t2, the level of condensate increases above thevolume threshold. Therefore, power is supplied to the CMS device. Assuch, controller 12 may begin to make adjustments based on the engineoperating conditions to deliver the collected condensate to the enginesystem. In the example shown, the load on the engine falls below thefirst load threshold identified as LT1 in the figure. Therefore, becausethe condensate is clean, and because the load on the engine falls belowa threshold output, the catalyst temperature is likely to be moderatelycool. Responsive to these conditions, controller 12 may thereby operatethe CMS in the third operating mode to deliver condensate to the thirdposition by adjusting the pathway to route the clean condensatedownstream of the catalyst. As such, the position of first routing valve210 is adjusted accordingly to the second position in order to routecondensate through second pathway 222, while the position of secondrouting valve 212 is also adjusted to its second position in order toroute the condensate through fourth pathway 226. As described above,this mode of operation advantageously discharges the clean condensate tothe atmosphere external to the vehicle and comes with a very lowprobability of engine misfire or hesitation.

The increased engine output between time t2 and time t3 may cause theCAC condensate level to further increase. At time t2, the engine outputincreases above LT1. Therefore, controller 12 may determine that theengine is to be operated in the second operating mode in order to routethe condensate upstream of the catalyst (plot 810). However, because thefirst routing valve is already in the second position, condensate isalready being delivered to the engine exhaust. As such, controller 12may simply adjust the second routing valve 212 to the first position inorder to adjust the pathway for delivery of the condensate to the secondposition. Then, based on the engine operating conditions (e.g., catalysttemperature), the amount of condensate injected may be adjusted to coolthe catalyst by spraying an atomized mist of clean condensate (e.g.,water) onto the catalyst via the engine exhaust manifold.

At time t3, the vehicle may decelerate and therefore reduce a loadproduced by the engine. In response to the engine output falling belowLT1, controller 12 may again operate the engine in the third mode todeliver condensate downstream of the catalyst. However, in otherinstances where the catalyst temperature remains high even though theengine output briefly falls below LT1, controller 12 may be programmedto maintain operation in the second mode to route the condensateupstream of the catalyst. For simplicity, herein, the catalysttemperature follows the engine output (plot 804). At t4, the vehicleagain accelerates and thereby increases the load on the engine. Inresponse, controller 12 makes adjustments to operate in the second modeby adjusting the second routing valve to the first position whilerouting the condensate upstream of the catalyst. Furthermore, sometimebetween time t4 and time t5, condensate sensor 410 determines thatengine oil is present in the condensate.

In response to detecting engine oil, controller 12 may re-route thecondensate/oil mixture to the air intake in order to burn the additionalcombustible material. Therefore, at t5, controller 12 may makeadjustments to operate in the first mode to deliver the mixture to theengine air intake (plot 810). Further, controller 12 may accomplish thissimply by adjusting first routing valve 210 back to the first position(plot 812) without adjusting second routing valve 212. Once firstrouting valve 210 has been adjusted to the first position, thecondensate mixture will flow through first pathway 220. Therefore,further adjustments to second routing valve 212 serve no functionalpurpose. For simplicity, in this example, controller 12 simply leavessecond routing valve 212 in the same position as was occupied just priorto the detection of the engine oil.

At t6, the engine output falls below the second load threshold (LT2).Therefore, a reduced airflow within the intake system due to lower airpath velocities may make it more difficult to distribute the injectedcondensate/oil mixture evenly to all of the cylinders since the atomizedmixture tends to settle along the floor of the air duct. As such,controller 12 may adjust the condensate pathway in order to deliver themixture to the third position even though discharge of engine oil to theatmosphere may adversely affect engine emissions. On the other hand, acleaner intake manifold may serve to enhance engine and/or vehicleoperations. At t7, the CAC condensate level decreases below the volumethreshold. In response, controller 12 may halt condensate deliveryoperations by turning off the CMS module (plot 808). Thereafter, thevehicle may continue to decelerate while the engine load furtherdecreases.

Turning to the second embodiment, FIGS. 9-14 show engine 10 including anauxiliary canister for storing pressurized air to aid in the routing ofcondensate under low engine operating conditions. In addition, thesecond embodiment further includes a passageway for directing condensateto each combustion chamber of the engine. As such, in some embodiments,the air routed into said combustion chambers may be further routed intoan air intake system comprising: an air intake coupled to an intakemanifold which is coupled to one or more intake runners each of which iscoupled to one of the combustion chambers. the method further includeswherein the accumulated air is coupled through the passage only when thecondensate is present and the engine output is below a predeterminedamount. Briefly, controller 12 may disable airflow form the accumulatorthrough the passageways when the engine output is above thepredetermined amount. However, the second embodiment is described withrespect to a low engine output for simplicity, and in furtherembodiments, the method includes wherein the predetermined amount of theengine output corresponds to high load engine conditions. Thus, theaccumulator may be additionally or alternatively engaged to delivercollected condensate under other engine operating conditions. Forexample, if the engine output is high (e.g., greater than the first loadthreshold), the accumulator may be engaged to produce an increasedpressure that serves to increase the rate of condensate delivery.

FIG. 9 shows an example condensation management system includingaccumulator 902 from a front view relative to the vehicle. Thecondensation management system includes features in common with thesystem described with respect to FIG. 4. As such, engine elementsdescribed there are not re-described here, although the various partsare identified in FIG. 9 for clarity. Briefly, air intake 42 may draw inair from one or more ducts (not shown). The one or more ducts may drawin cooler or warmer air from outside the vehicle or underneath the hoodof the vehicle, respectively. The intake air may travel downstream toCAC 166 where the air is further cooled. To aid in cooling the chargeair, ambient airflow from outside the vehicle may enter engine 10through a vehicle front end and pass across CAC 166. Thus, the heatexchanger comprises an air to air heat exchanger and includes areservoir to collect the condensate. In response, condensate may form inthe CAC when the charge air is cooled below the water dew point.

Condensate collected at the bottom of CAC 166, may then be re-introducedto the engine system at one of three position based on the type ofcontaminate sensed in the condensate. As mentioned above, thecondensation management system according to the second embodimentfurther includes accumulator 902 for storing pressurized air. Thus, themethod comprises routing air from a compressor through a heat exchangerto a combustion chamber of the engine; coupling condensate formed in theheat exchanger through a passage coupled to the combustion chamber;accumulating a portion of the compressed air in an accumulator; and whenthe engine output is below a predetermined amount, coupling a part ofthe accumulated air through the passage into the combustion chamber,wherein said compressor is driven by a turbo positioned in the engineexhaust, or by a mechanical coupling to a crankshaft or a camshaft ofthe engine.

As shown in the example of FIG. 9, accumulator 902 is coupled to thecondensation management system in an arrangement whereby a portion ofair from the intake system may be directed into the auxiliary canisterstorage tank under some conditions to increase the pressure therein. Forthis reason, accumulator 902 includes inlet 910 for connecting theintake system to accumulator 902. Accumulator inlet 910 further includesfirst accumulator valve 912 for controlling an opening within the inletline. Because accumulator 902 is configured to route and assist themovement of condensate to the engine using pressurized air stored withinthe auxiliary canister, accumulator outlet 920 is included forconnecting the storage tank to the inlet assembly 202, which furtherincludes first routing valve 210 (not shown). Accumulator outlet 920also includes a valve referred to as second accumulator valve 922 forcontrolling an opening within the outlet line. Thus, the two valves canbe controlled to fill and empty the canister based on a desiredoperation of the accumulator (e.g., to route said condensate).

For example, to increase the amount of air stored within accumulator902, which increases the pressure within the storage tank, firstaccumulator valve 912 can be opened while second accumulator valve 922remains closed. Although accumulator filling may occur over a broadrange of drive cycles, heavy tip-in, over-boost, and/or rapiddeceleration events may represent desirable times to capture thisotherwise wasted energy. In this way, the system and methods describedherein may further enhance the overall system efficiency. In addition,charging of the accumulator at these example times may advantageously beperformed in a manner that is unnoticeable by the vehicle occupants.Then, once the canister has been substantially filled, for instance,because the stored boost pressure exceeds a pressure threshold, firstaccumulator valve 912 can be closed to allow storage of the pressurizedair until its later use by the system. In order to deliver condensatebased on the engine conditions, controller 12 may be configured to opensecond accumulator valve 922 to increase the airflow therein forincreasing the rate of condensate delivery via the routing of thecondensate to one of the engine positions. In this way, the accumulatormay temporarily increase a pressure in the condensate management systemto force a delivery of the collected condensate via an injector. Uponcompletion of the condensate delivery, second accumulator valve 922 maythen be actuated to a closed position to prevent additional airflow fromflowing through accumulator outlet 922. In another embodiment,controller 12 may be configured to adjust an amount of opening of secondaccumulator valve 922 to adjust the rate of condensate delivery. Forexample, the degree of valve opening may be increased to increase theairflow through accumulator 902, and therefore the rate of condensatedelivery. Alternatively, the degree of valve opening may be decreased todecrease an airflow from accumulator 902. In this way, the accumulatorallows for the condensate to be delivered using the stored pressurizedair.

With regard to the air flowing through CAC 166, as air exits the chargeair cooler, the intake airflow proceeds to engine 10 via intake manifold47. FIG. 9 further illustrates that condensate directed to the engineair intake may be routed directly to one or more combustion cylinders ofthe engine. As such, first pathway 220 is shown extending to a topportion of the engine (not shown) with branching lines 932 that lead toeach cylinder of the example multi-cylinder engine. Therefore, insteadof routing said condensate to the first position located along theintake manifold, in some embodiments, the condensate may be injecteddirectly into the combustion chambers of the engine. Although not shown,branching lines 932 may also include valves for controlling a rate ofcondensate delivery to one or more cylinders. Therefore, in someinstances, condensate delivery may be evenly distributed to the enginecylinders while in other instances, condensate may be unevenlydistributed to the engine cylinders, for example, by injecting increasedamounts of condensate to one or more cylinders relative to the remainingcylinders.

FIG. 10 illustrates an example coupling of accumulator outlet 920 tofirst routing valve 210. For simplicity, FIG. 10 shows the examplecondensation management system of FIG. 9 from a rear view relative tothe vehicle. As described above, accumulator outlet 920 connectsaccumulator 902 into first routing valve 210. When configured in thismanner, the pressurized contents stored within accumulator 902 can bedirected into the condensation management system and further used todeliver a boost pressure capable of routing the condensate to the threepositions within engine 10. In addition, because a pressurized system isused, the added boost pressure can be used to deliver condensate to oneor more engine cylinders located at a top portion of engine 10 relativeto the lowest point of CAC 166 where condensate collects. The storedboost pressure may be used in combination with other pressures withinthe engine system for routing said condensate. Although an accumulatoris included for delivering condensate based on a pressure due to anairflow, in other embodiments, engine 10 and condensate managementsystem 200 may employ a vacuum concept whereby a lower pressure withinthe engine system is used to pull (or force) the flow of condensate.However, although structural features are different for implementing thevacuum-based system, similar concepts are used as described herein.

FIG. 11 shows an example valve assembly coupled to the accumulatoroutlet in greater detail. As shown, accumulator outlet 920 may beconnected to first routing valve 210. Although second accumulator valve922 is shown near accumulator 902 in FIGS. 10 and 11, in someembodiments, second accumulator valve 922 may alternatively be locatednear first routing valve 210. In still other embodiments, first routingvalve 210 may be configured to include the second accumulator valveintegrated therein. As such, first routing valve 210 may alternativelycontrol a degree of opening of the outlet valve in order to control aflow of condensate from CAC 166.

FIG. 12 shows an example multi-port system for distributing routedcondensate to individual cylinders of the engine in greater detail. Forsimplicity, only the bottom half of intake manifold 47 is shown toillustrate the orientation of branching lines 932 relative to thecombustion cylinders of the engine

With respect to accumulator control, FIGS. 13 and 14 show example flowcharts for making adjustments to increase a delivery pressure whenrouting said condensate. Therefore, although not shown explicitly,accumulator 902 may also communicate with controller 12, which may beconfigured to make one or more adjustments based on engine operatingconditions in order to engage the accumulator.

FIG. 13 illustrates an example flow chart of method 1300 for routingcondensate using the accumulator. At 1302, method 1300 includesmonitoring one or more engine conditions to determine when engagement ofthe accumulator for routing the condensate is to occur. For example,when an engine output is low, delivery of the condensate may becomedifficult. Therefore, a portion of the pressure stored withinaccumulator 902 may be used to force condensate to a location within theengine system based on the composition of the collected condensate. Assuch, at 1304, method 1300 includes determining whether an engine outputis below a threshold (e.g., below the second or fourth thresholds).Then, if a low engine load is detected, at 1306, method 1300 includesrouting the condensate using a portion of the stored boost pressure. Themethod further includes actuating second accumulator valve 922 to forcecondensate through one or more passageways of the engine system.Although, actuating the second accumulator valve 922 is described hereinfor simplicity, in some embodiments, another valve may be alternativelyengaged, for example, because accumulator valve 922 is integrated intofirst routing valve 210. Thereby, other valve configurations arecontemplated for routing condensate through the engine system. At 1308,method 1300 further includes metering the rate of condensate deliverybased on engine operating conditions and the stored boost pressure. Forexample, if the stored boost pressure is high (e.g., above a thresholdpressure), a flow rate or boost may be increased by increasing a degreeof valve opening in accumulator outlet 920. Alternatively, if thepressure in accumulator 902 is low (e.g., falls below the thresholdpressure), controller 12 may decrease a flow rate by decreasing a degreeof valve opening while still providing added boost to deliver thecondensate.

Returning to 1304, if the engine output does not fall below a loadthreshold, at 1306, method 1300 may include not engaging the accumulatorto route said condensate. However, in alternative methods, controller 12may be programmed to engage the accumulator in order to increase a rateof condensate flow even when a load on the engine is high.

Briefly, as described above, when the system according to the presentdisclosure includes an accumulator, the method comprises: coupling saidcondensate to the light off catalyst when the engine output is above apreselected amount and the condensate is substantially free of thecontaminate and the light of catalyst is above a predeterminedtemperature. The system further comprises an engine exhaust coupled toan exhaust of one or more combustion chambers and a coupling between acondensate collecting reservoir and a position in said exhaustdownstream of said catalyst. Thereby, the controller may couple thecondensate to the position downstream of the catalyst while disabling anairflow from the accumulator through the passageways when an engineoutput is below a predetermined amount in a particular operatingcondition. Further, the particular operating condition may include apressure in the accumulator below a threshold value. In addition, themethod comprises an engine exhaust coupled to an exhaust of one or moreof the combustion chambers and a coupling between the condensatecollecting reservoir and a position in said exhaust upstream of saidcatalyst. Therefore, the system includes a controller that couples thecondensate to the position upstream of the catalyst and disabling anairflow from the accumulator through the passageways when the engineoutput is above a predetermined amount and temperature of the catalystis above a preselected amount.

With respect to the filling of an empty auxiliary canister, FIG. 14illustrates example method 1400 for filling the accumulator withpressurized gas. As such, airflow from CAC outlet tank 45 may bedirected to accumulator 902 through accumulator intake 910 under someengine operating conditions. Therefore, control system 12 may beconfigured to actuate one or more valves based on the engine operatingconditions, as shown at 1402.

At 1404, engine 10 may be configured to detect a pressure withinaccumulator 902 relative to a pressure threshold that is used toindicate an amount of pressurized air within the accumulator. Althoughnot shown explicitly, accumulator 902 may further include a pressuresensor to indicate the stored boost pressure in some embodiments. If thestored boost pressure exceeds the first pressure threshold thatindicates a low content level, at 1406 controller 12 may direct air intoaccumulator 902 during an episode of high engine output (e.g., engineoutput above the first or third threshold) while the airflow therein isincreased. In response, at 1410, method 1400 may adjust secondaccumulator valve 922 to the closed position to allow airflow directedtoward the storage tank to be stored while preventing further flow fromexiting the auxiliary canister. Then, at 1412, method 1400 includesactuating first accumulator valve 912 to an open position to allowairflow to accumulator 902 through the inlet line. Alternatively, if thestored boost pressure does not fall below the first pressure threshold,at 1430, method 1400 may determine that sufficient contents are storedwithin accumulator 902. In this case, controller 12 may be programmed toprevent the addition of further contents by, for example, actuating oneor more of the first and second accumulator valves to the closedposition.

Additionally, at 1420, a second pressure threshold is included toindicate storage canister that is substantially full. Upon reaching thesecond higher pressure threshold, at 1422, method 1400 may actuate firstaccumulator valve 912 to the closed position to store the contentstherein until a time when the pressurized contents are to be used forrouting the condensate. Alternatively, while the pressure falls belowthe second pressure threshold, at 1424, the method may continue fillingthe auxiliary canister based on engine operating conditions. In otherwords, as long as the pressure in the intake system exceeds the tankpressure, air may flow in the direction of the canister. Therefore, theinlet valve may remain open to increase the stored boost pressure byincreasing the amount of contents contained within the storage tank. Thefeedback cycle may continue until the auxiliary canister has beenfilled. For clarity, although not shown, method 1400 further includesdelivering condensate using the pressurized contents stored within theauxiliary canister while the canister is simultaneously filled. In otherwords, sufficient pressure may exist in the canister to allow the secondaccumulator valve 922 to be opened while first accumulator valve 912 isalso open. Controller 12 may thus be configured to make one or morevalve adjustments based on a determined rate of boost pressure deliveredfrom the canister in relation to the rate of boost pressure delivered tothe canister.

FIGS. 15 and 16 show a third embodiment for routing collected condensateto engine 10. In the third embodiment, an inline engine is shown whereinthe lowest point in the intake system resides in intake manifold 47rather than beneath CAC 166 as described above. This is because engine10 according to the third embodiment includes an air to water heatexchanger as opposed to an air to air heat exchanger as described abovefor the V-engine configuration having an air to air heat exchanger(e.g., CAC 166). As described herein, in this engine configuration,which is illustrated with respect to an inline engine, condensate doesnot collect within the heat exchanger as described above. In addition,substantially no pressure differential forms across the heat exchangerbecause the air to water heat exchanger has a reduced size compared toCAC 166. Thus, routing collected condensate to various locations withinthe engine system presents additional distribution challenges that aresolved using an accumulator to aid in the distribution of condensateunder all engine operating conditions. For these reasons, the thirdembodiment includes a reservoir that has been relocated to the lowestpoint in the intake system where condensation collects, namely theintake manifold plenum. Accumulator 902 is also included to forcecondensate collected in said reservoir through the various passageways.

FIG. 15 shows a side view of the third embodiment of the condensationmanagement system. The third embodiment relates to an inline engineconfiguration that may be installed within the engine compartment in anypower-train position. For example, in some embodiments, the orientationof the inline engine defined by the linear direction of the runners maybe parallel to the longitudinal axis of the vehicle while in otherembodiments the orientation of the engine may be orthogonal to thelongitudinal axis of the vehicle. In addition, a system according to thethird embodiment allows for the turbocharger to be arranged in anyconfiguration. In this way, an increased design flexibility of theengine can be realized. In FIG. 15, the inline engine is arrangedperpendicular to the longitudinal axis of the vehicle so the view shownrepresents a side view of the engine.

In the inline engine according to the third embodiment, the collectionarea is located within intake manifold 47. Therefore, condensate iscollected in condensate reservoir 1502 that is re-located to the lowestpoint within intake manifold 47. As such air that enters CAC inlet tank42 may be cooled as it flows through CAC 1566, which is shown as a waterto air charge air cooler. Then, as the airflow continues through intakemanifold 47, condensate may collect at reservoir 1502. As describedabove, reservoir 1502 may be configured to include inlet tank assembly202 for routing said collected condensate throughout engine 10 in themanner already described. In addition, accumulator 902 may bereconfigured based on the structure of the engine and intake system. Forexample, FIG. 15, shows accumulator inlet 910 in communication with CAC1566 outlet tank 45. Therefore, airflow within the system may bedirected to the auxiliary canister to increase the stored boost pressurewithin accumulator 902 in the same manner described above. Accumulator902 further connects to routing valve 210 via inlet tank assembly 202.As described below with respect to FIG. 16, the inline engine furtherincludes an intake manifold coupled to engine runners 1510 for directingthe airflow to combustion chambers within the engine. Thus, intakemanifold 47 connects to a plurality of intake runners 1510 that lead tocombustion chambers within engine 10. In addition, first pathway 220 isshown as multiple passageways, wherein each of said passageways arecoupled to one of a plurality of intake runners each of whichcommunicates with a corresponding one of said combustion chambers, andwherein the reservoir communicates with each of the passageways, andwherein the accumulator communicates with the reservoir.

To illustrate these connections in greater detail, FIG. 16 shows thethird embodiment of the condensation management system from a frontview. As described briefly above, condensate reservoir 1502 is locatedat the lowest point within intake manifold 47. The example inline enginefurther includes multiple combustion chambers, an air intake manifoldand intake runners coupling the manifold to the intake runners, and anexhaust coupled to a light off catalyst (not shown); a turbochargerhaving a turbo coupled to the exhaust and a compressor driven by theturbo (not shown); a heat exchanger having an input connected to thecompressor and an output coupled to the combustion chambers through theintake manifold and the intake runners; and a reservoir connected to theheat exchanger and a plurality of passageways each connected between thereservoir and each of the intake runners to route condensate to thecombustion chambers; an accumulator having an input coupled to thecompressor and an output coupled to each of the passageways; and acontroller controlling airflow from the accumulator through thepassageways. In FIG. 16, first pathway 220 that is a passageway forconnecting inlet tank assembly 202 to the intake system includesmultiple branching lines 932 for coupling the condensate reservoir toindividual runners of the engine. Thereby, routing the condensate toeach combustion chamber of the engine may be individually orcollectively controlled to control a distribution of the condensate tothe intake system.

In this way, the system and methods according to the present disclosuremay be used to remove collected condensate from the charge air coolerduring vehicle operation. Furthermore, routing the condensate to eitherthe air intake system or a position in the engine exhaust based uponboth the type of contaminate in the condensate and operating parametersof the engine or the catalyst offers additional advantages for coolingthe catalyst during high engine loads. For example, when the engine isoperating at a high load in the absence of engine oil (e.g., because itis not present as a contaminate), the condensate may be routed into theengine exhaust upstream of the catalyst to cool the catalyst. In anotherexample, when the engine is operating at a high load and engine oil ispresent in the contaminate, the condensate may be routed into the engineair intake to combust the oil without contaminating the catalyst. Instill another aspect, engine power may be reduced when engine coolant isin the condensate to allow the operator to drive to a safe place withoutharming the engine.

Note that routing condensate to either said combustion chamber or aposition in the engine exhaust (or another, different, position in theengine system) may be based upon a contaminate in said condensate andoperating parameters of the engine and/or the catalyst, such operationmay include routing condensate to each of these positions underdifferent conditions. For example, the routine may include routingcondensate to said combustion chamber, and routine condensate to aposition in the engine exhaust, and routine condensate to another,different, position in the engine system, based upon an amount ofcontaminate in said condensate and operating parameters of the engineand/or the catalyst. One embodiment may include routing condensate onlyto the combustion chamber for a first amount of contaminate in thecondensate, routing condensate only to the engine exhaust, for a secondamount of contaminate in the condensate, and routing condensate only toanother, different, position in the engine system for a third amount ofcontaminate, and or based on operating parameters of the engine and/orthe catalyst.

Note that the example control and estimation routines included hereincan be used with various engine and/or vehicle system configurations.The control methods and routines disclosed herein may be stored asexecutable instructions in non-transitory memory. The specific routinesdescribed herein may represent one or more of any number of processingstrategies such as event-driven, interrupt-driven, multi-tasking,multi-threading, and the like. As such, various actions, operations,and/or functions illustrated may be performed in the sequenceillustrated, in parallel, or in some cases omitted. Likewise, the orderof processing is not necessarily required to achieve the features andadvantages of the example embodiments described herein, but is providedfor ease of illustration and description. One or more of the illustratedactions, operations and/or functions may be repeatedly performeddepending on the particular strategy being used. Further, the describedactions, operations and/or functions may graphically represent code tobe programmed into non-transitory memory of the computer readablestorage medium in the engine control system.

It will be appreciated that the configurations and routines disclosedherein are exemplary in nature, and that these specific embodiments arenot to be considered in a limiting sense, because numerous variationsare possible. For example, the above technology can be applied to V-6,I-4, I-6, V-12, opposed 4, and other engine types. The subject matter ofthe present disclosure includes all novel and non-obvious combinationsand sub-combinations of the various systems and configurations, andother features, functions, and/or properties disclosed herein.

The following claims particularly point out certain combinations andsub-combinations regarded as novel and non-obvious. These claims mayrefer to “an” element or “a first” element or the equivalent thereof.Such claims should be understood to include incorporation of one or moresuch elements, neither requiring nor excluding two or more suchelements. Other combinations and sub-combinations of the disclosedfeatures, functions, elements, and/or properties may be claimed throughamendment of the present claims or through presentation of new claims inthis or a related application. Such claims, whether broader, narrower,equal, or different in scope to the original claims, also are regardedas included within the subject matter of the present disclosure.

1. A method for an engine having an exhaust coupled to a catalyst,comprising: routing air through a heat exchanger and into one or morecombustion chambers of the engine; forming a condensate in said heatexchanger; and routing said condensate to either said combustion chamberor a position in the engine exhaust based upon a contaminate in saidcondensate and operating parameters of the engine or the catalyst. 2.The method recited in claim 1 wherein said air routed into saidcombustion chambers is routed into an air intake system comprising: anair intake coupled to an intake manifold which is coupled to one or moreintake runners each of which is coupled to one of said combustionchambers.
 3. The method recited in claim 2 wherein said condensate isrouted to a first position along said engine air intake system in afirst mode of operation, and a second position along the engine exhaustin a second mode of operation, and a third position along the engineexhaust in a third mode of operation.
 4. The method recited in claim 3wherein said first mode of operation comprises engine operation at ahigh load with said contaminate including engine oil.
 5. The methodrecited in claim 3 wherein said first mode of operation comprises engineoperation under fuel enrichment conditions with said contaminateincluding engine oil.
 6. The method recited in claim 3 wherein saidsecond position along the engine exhaust is upstream of the catalyst andsaid second mode of operation comprises engine operation at a high loadwith said contaminate being substantially free of engine oil.
 7. Themethod recited in claim 3 wherein said second mode of operationcomprises the catalyst operating at a temperature inferred to be above apredetermined temperature with said contaminate being substantially freeof engine oil.
 8. The method recited in claim 7 wherein catalysttemperature is inferred from one or more of the following variables:combustion air/fuel ratio, exhaust gas recirculation, engine speed,ignition timing, and airflow through the engine.
 9. The method recitedin claim 1 further comprising reducing power to the engine when saidcontaminate includes engine coolant.
 10. The method recited in claim 3wherein said third position along the engine exhaust is downstream ofthe catalyst and said third mode of operation comprises engine operationat a low load and no significant engine oil is detected in saidcondensate.
 11. The method recited in claim 10 wherein said operation insaid third mode with said condensate routed to said third positionoccurs more often than said operation in said second mode with saidcondensate routed to said second position or said operation in saidfirst mode with said condensate routed to said first position.
 12. Themethod of claim 1 wherein said heat exchanger comprises an air to airheat exchanger and includes a reservoir to collect said condensate. 13.The method recited in claim 2 wherein said heat exchanger comprises aliquid to air heat exchanger and said condensate is collected from saidintake manifold.
 14. A method for an engine system having an engine airintake system and a light off catalyst coupled to an engine exhaust,comprising: compressing air in a compressor driven by a turbo coupled tothe engine exhaust upstream of the catalyst; forcing said compressed airthrough a heat exchanger into the engine air intake system; collectingcondensate formed by the heat exchanger in a reservoir connected to saidheat exchanger; when the engine is operating at a high load and engineoil is not present in said condensate, routing said condensate into theengine exhaust upstream of the catalyst and downstream of the turbo;when the engine is operating at a high load and engine oil is present insaid condensate, routing said condensate into a position in the airintake system; and when the engine is operating at a low or moderateload, routing said condensate to either the intake system or to theengine exhaust downstream of the catalyst.
 15. The method recited inclaim 14 wherein said condensate is routed into the engine exhaustupstream of the catalyst and downstream of the turbo when the engine isoperating under fuel enrichment conditions and engine oil is not presentin said condensate.
 16. The method recited in claim 14 wherein saidcondensate is routed into the air intake system when engine oil ispresent in said condensate and the engine is operating under fuelenrichment conditions.
 17. The method recited in claim 14 furthercomprising reducing power to the engine when engine coolant is presentin said condensate.
 18. The method recited in claim 14 wherein the airintake system comprises: an air intake coupled to an intake manifoldwhich is coupled to one or more intake runners each of which is coupledto a combustion chamber of the engine.
 19. An engine system having anengine air intake, and a light off catalyst coupled to an engineexhaust, comprising: a turbocharger having a compressor driven by aturbo coupled to the engine exhaust upstream of the catalyst; a heatexchanger having an input coupled to said compressor and an outletcoupled to the air intake system; a reservoir coupled to a bottom ofsaid heat exchanger to collect condensate formed by the heat exchanger;at least one sensor to detect a presence of engine oil and a presence ofengine coolant in said condensate; a first metering valve coupledbetween said reservoir and the air intake system; a second meteringvalve coupled between said reservoir and the engine exhaust upstream ofthe catalyst and downstream of said turbo; a third metering valvecoupled between said reservoir and the engine exhaust downstream of thecatalyst; and a controller to control said first, second and thirdmetering valves based upon said detection of engine oil or absence ofsaid engine oil, to route said condensate as follows: activating saidfirst metering valve when the engine is operating at a high load andsaid contaminate detection indicates engine oil is present; andactivating said second metering valve when the engine is operating at ahigh load and said contaminate detection indicates engine oil is notpresent.
 20. The system recited in claim 19 wherein said controlleractivates said third metering valve when the engine is operating at alow or moderate load.
 21. The system recited in claim 19 wherein saidcontroller activates said first metering valve when the engine isoperating at a low or moderate load.